What I mean is what if the Thalmor aren't beaten by the Empire or any Altmer faction, but instead are beaten by a race from outside Tamriel? Like the Maormer sea elves. Or the Sload. Or one of the Akaviri races, though it would be a long distance to travel. Or for that matter, what if the Empire is beaten by one of the same instead of the Thalmor? How would you feel about that? In my opinion it would be neat to see one of the more obscure factions play a bigger role, and to see the balance of power so severely upset. And it could be explained as an opportunistic act taking advantage of both sides being focused on each other, rather than the outside. And the Maormer have long been hostile to the Altmer. This could be the perfect opportunity to strike.

I wouldn't like this, I'd feel cheated of the opportunity to put them down myself. The thalmor should fall in game by the hand of a player character

What if the player character works for, or is a Sea elf, or Sload, or whatever though?

You forgot to mention the Borg!

What?

I was trying to be funny and it fell flat. Sorry!